Class NVDrawVulkanImage

This extension provides a new function, DrawVkImageNV, allowing applications to draw a screen-aligned rectangle displaying some or all of the
contents of a two-dimensional Vulkan VkImage. Callers specify a Vulkan VkImage handle, an optional OpenGL sampler object, window coordinates of
the rectangle to draw, and texture coordinates corresponding to the corners of the rectangle. For each fragment produced by the rectangle,
DrawVkImageNV interpolates the texture coordinates, performs a texture lookup, and uses the texture result as the fragment color.

No shaders are used by DrawVkImageNV; the results of the texture lookup are used in lieu of a fragment shader output. The fragments generated
are processed by all per-fragment operations. In particular, DrawVkImageNV() fully supports blending and multisampling.

In order to synchronize between Vulkan and OpenGL there are three other functions provided; WaitVkSemaphoreNV, SignalVkSemaphoreNV and
SignalVkFenceNV. These allow OpenGL to wait for Vulkan to complete work and also Vulkan to wait for OpenGL to complete work. Together OpenGL and
Vulkan can synchronize on the server without application interation.

Finally the function GetVkProcAddrNV() is provided to allow the OpenGL context to query the Vulkan entry points directly and avoid having to
load them through the typical Vulkan loader.

glSignalVkSemaphoreNV

public static void glSignalVkSemaphoreNV​(long vkSemaphore)

Causes the GL server to signal the Vulkan VkSemaphore when it executes this command. The semaphore is not signalled by GL until all commands
issued before this have completed execution on the GL server.

glSignalVkFenceNV

public static void glSignalVkFenceNV​(long vkFence)

Causes the GL server to signal the Vulkan VkFence object when it executes this command. The fence is not signalled by the GL until all commands
issued before this have completed execution on the GL server.